The thalassemia syndromes are inherited anemias associated with deficient or absent synthesis of specific globin chains of normal hemoglobin. In the most common variety, the messenger RNA encoding the beta globin chain is quantitatively deficient. The reason for this is unknown. The proposed work is designed to examine the synthesis of globin RNA in normal and thalassemic individuals to ascertain whether this deficiency is the result of reduced synthesis or abnormal stability of mutant RNA. These studies should eventually pinpoint the molecular defects in these severe, inherited anemias.